Mississippi v. Tennessee - 142 S. Ct. 31 (2021)

Rule:

Under the equitable apportionment doctrine, the Supreme Court allocates rights to a disputed interstate water resource after one State sues another under the Court’s original jurisdiction.

Facts:

Mississippi brought an original action against Tennessee for damages related to the pumping of groundwater by the City of Memphis from the Middle Claiborne Aquifer. Mississippi expressly disclaims any equitable apportionment remedy, arguing that the fundamental premise of this Court’s equitable apportionment jurisprudence does not apply to the dispute. A Special Master was appointed by the Court to assess Mississippi’s claims. 

Issue:

Can the waters of the Middle Claiborne Aquifer be subject to the judicial remedy of equitable apportionment?

Answer:

Yes.

Conclusion:

The Court held that the waters of the Middle Claiborne Aquifer were subject to the judicial remedy of equitable apportionment, and that Mississippi had failed to show that it was entitled to relief. Equitable apportionment of the Middle Claiborne Aquifer would be sufficiently similar to past applications of the doctrine to warrant the same treatment. Therefore, the Court dismissed the complaint without leave to amend.